Our Stage 4 Conversion for Astra & Zafira VXR (Z20LEH) builds on the Stage 3 hardware components that are: . Full Exhaust System, preferably 3” (76mm) throughout . Large Intercooler To this we add the following: . K06 Hybrid Turbo . Klasen High Flow Inlet Manifold . Stage 4 Software With our Stage 4 we […]